The two major goals of the proposed research are to provide better estimates of the genetic and environmental variances and covariances for intellectual, personality, and attitudinal measures in the white population and to estimate the range of reaction for intellectual characteristics in black and white populations. The first study includes large samples of adoptive families, natural families and separated siblings. Data on related and unrelated children (ages 16 to 21) reared together and apart, will be obtained. Parent-child correlations for adoptive and natural families and natural mothers of adopted children will also be calculated. From these data, estimates of the variance components in intellectual, personality and attitudinal characteristics of the population will be made. The second study includes two samples of white adoptive parents, one sample with black adopted children and the other with white adopted children. The adoptive parents will be equated for socioeconomic characteristics and racial attitudes. Mean scores in the two samples of adopted children will be compared, and parent-child correlations calculated.